Gmail has added a new feature today which allows you to restore accidentally deleted contacts. This feature works back up to 30 days and the contact will be restored with same details as it was in at that time.
All you need to do is go to Gmail’s Contacts section, hit “More Actions,” and go to “Restore Contacts.”
This will open a small browser overlay window giving you a list of times from which you can restore your address book. The options include restoring contacts deleted in the 10 minutes to a week ago. However, if you you had deleted someone a couple of weeks ago, choose the “Custom” option and enter a date of your choice. Finally hit the “Restore” button.
This will restore your contacts to the same state they were at your chosen time. And, if you make a mistake and restore it to a point too far back, you can always move it back forward.
This is a nice little feature if you’re using Google Contacts as your central, unified address book.
Check out this post to know how you can restore deleted contacts in hotmail.